<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<script src="https://cdn.bootcdn.net/ajax/libs/jquery/3.5.1/jquery.min.js"></script>
</head>
<body>
<div id="tag">这是div</div>
<script>
document.getElementById('tag').innerHTML='这是改变后的内容，可以覆盖原来的内容';
</script>
</body>
</html>